The storied New York City skyline gets a surge of exhilaration with the first worthy addition of the century

If you like turmoil, architecture is the place to be right now. The last time the field had something like a prevailing style was in the 1970s, at what appeared to be the tail end of Modernism. It was a moment when everybody knew the formula for a successful building--Glass+Steel=Box--and everybody was sick of it.

We live now in a creative free-for-all, when Deconstruction, Expressionism and a half a dozen other unorthodoxies reign. But as it turns out, Modernism never actually died. What it did was evolve--sometimes into something really interesting. To see what that means right now just stand at the...